2 * security-core-clr.c: CoreCLR security
5 * Mark Probst <mark.probst@gmail.com>
6 * Sebastien Pouliot <sebastien@ximian.com>
8 * Copyright 2007-2009 Novell, Inc (http://www.novell.com)
11 #include <mono/metadata/class-internals.h>
12 #include <mono/metadata/security-manager.h>
13 #include <mono/metadata/assembly.h>
14 #include <mono/metadata/appdomain.h>
15 #include <mono/metadata/verify-internals.h>
16 #include <mono/metadata/object.h>
17 #include <mono/metadata/exception.h>
19 #include "security-core-clr.h"
21 gboolean mono_security_core_clr_test = FALSE;
24 security_critical_attribute (void)
26 static MonoClass *class = NULL;
29 class = mono_class_from_name (mono_defaults.corlib, "System.Security",
30 "SecurityCriticalAttribute");
37 security_safe_critical_attribute (void)
39 static MonoClass *class = NULL;
42 class = mono_class_from_name (mono_defaults.corlib, "System.Security",
43 "SecuritySafeCriticalAttribute");
50 * mono_security_core_clr_check_inheritance:
52 * Determine if the specified class can inherit from its parent using
53 * the CoreCLR inheritance rules.
55 * Base Type Allow Derived Type
56 * ------------ ------------------
57 * Transparent Transparent, SafeCritical, Critical
58 * SafeCritical SafeCritical, Critical
61 * Reference: http://msdn.microsoft.com/en-us/magazine/cc765416.aspx#id0190030
64 mono_security_core_clr_check_inheritance (MonoClass *class)
66 MonoSecurityCoreCLRLevel class_level, parent_level;
67 MonoClass *parent = class->parent;
72 class_level = mono_security_core_clr_class_level (class);
73 parent_level = mono_security_core_clr_class_level (parent);
75 if (class_level < parent_level)
76 mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD, NULL);
80 * mono_security_core_clr_check_override:
82 * Determine if the specified override can "legally" override the
83 * specified base method using the CoreCLR inheritance rules.
85 * Base (virtual/interface) Allowed override
86 * ------------------------ -------------------------
87 * Transparent Transparent, SafeCritical
88 * SafeCritical Transparent, SafeCritical
91 * Reference: http://msdn.microsoft.com/en-us/magazine/cc765416.aspx#id0190030
94 mono_security_core_clr_check_override (MonoClass *class, MonoMethod *override, MonoMethod *base)
96 MonoSecurityCoreCLRLevel base_level = mono_security_core_clr_method_level (base, FALSE);
97 MonoSecurityCoreCLRLevel override_level = mono_security_core_clr_method_level (override, FALSE);
98 /* if the base method is decorated with [SecurityCritical] then the overrided method MUST be too */
99 if (base_level == MONO_SECURITY_CORE_CLR_CRITICAL) {
100 if (override_level != MONO_SECURITY_CORE_CLR_CRITICAL)
101 mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD, NULL);
103 /* base is [SecuritySafeCritical] or [SecurityTransparent], override MUST NOT be [SecurityCritical] */
104 if (override_level == MONO_SECURITY_CORE_CLR_CRITICAL)
105 mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD, NULL);
110 * get_caller_no_reflection_related:
112 * Find the first managed caller that is either:
113 * (a) located outside the platform code assemblies; or
114 * (b) not related to reflection and delegates
116 * Returns TRUE to stop the stackwalk, FALSE to continue to the next frame.
119 get_caller_no_reflection_related (MonoMethod *m, gint32 no, gint32 ilo, gboolean managed, gpointer data)
121 MonoMethod **dest = data;
124 /* skip unmanaged frames */
128 if (m->wrapper_type != MONO_WRAPPER_NONE)
131 /* quick out (any namespace not starting with an 'S' */
132 ns = m->klass->name_space;
133 if (!ns || (*ns != 'S')) {
138 /* stop if the method is not part of platform code */
139 if (!mono_security_core_clr_is_platform_image (m->klass->image)) {
144 /* any number of calls inside System.Reflection are allowed */
145 if (strcmp (ns, "System.Reflection") == 0)
148 /* any number of calls inside System.Reflection are allowed */
149 if (strcmp (ns, "System.Reflection.Emit") == 0)
152 /* calls from System.Delegate are also possible and allowed */
153 if (strcmp (ns, "System") == 0) {
154 const char *kname = m->klass->name;
155 if ((*kname == 'A') && (strcmp (kname, "Activator") == 0))
158 // the security check on the delegate is made at creation time, not at invoke time
159 if (((*kname == 'D') && (strcmp (kname, "Delegate") == 0)) ||
160 ((*kname == 'M') && (strcmp (kname, "MulticastDelegate")) == 0)) {
162 // if we're invoking then we can stop our stack walk
163 if (strcmp (m->name, "DynamicInvoke") != 0)
178 * get_reflection_caller:
180 * Walk to the first managed method outside:
181 * - System.Reflection* namespaces
182 * - System.[MulticastDelegate]Delegate or Activator type
184 * and return a pointer to its MonoMethod.
186 * This is required since CoreCLR checks needs to be done on this "real" caller.
189 get_reflection_caller (void)
191 MonoMethod *m = NULL;
192 mono_stack_walk_no_il (get_caller_no_reflection_related, &m);
194 g_warning ("could not find a caller outside reflection");
199 * check_field_access:
201 * Return TRUE if the caller method can access the specified field, FALSE otherwise.
204 check_field_access (MonoMethod *caller, MonoClassField *field)
206 /* if get_reflection_caller returns NULL then we assume the caller has NO privilege */
208 MonoClass *klass = (mono_field_get_flags (field) & FIELD_ATTRIBUTE_STATIC) ? NULL : mono_field_get_parent (field);
209 return mono_method_can_access_field_full (caller, field, klass);
215 * check_method_access:
217 * Return TRUE if the caller method can access the specified callee method, FALSE otherwise.
220 check_method_access (MonoMethod *caller, MonoMethod *callee)
222 /* if get_reflection_caller returns NULL then we assume the caller has NO privilege */
224 MonoClass *klass = (callee->flags & METHOD_ATTRIBUTE_STATIC) ? NULL : callee->klass;
225 return mono_method_can_access_method_full (caller, callee, klass);
231 * mono_security_core_clr_ensure_reflection_access_field:
233 * Ensure that the specified field can be used with reflection since
234 * Transparent code cannot access to Critical fields and can only use
235 * them if they are visible from it's point of view.
237 * A FieldAccessException is thrown if the field is cannot be accessed.
240 mono_security_core_clr_ensure_reflection_access_field (MonoClassField *field)
242 MonoMethod *caller = get_reflection_caller ();
243 /* CoreCLR restrictions applies to Transparent code/caller */
244 if (mono_security_core_clr_method_level (caller, TRUE) != MONO_SECURITY_CORE_CLR_TRANSPARENT)
247 /* Transparent code cannot [get|set]value on Critical fields */
248 if (mono_security_core_clr_class_level (mono_field_get_parent (field)) == MONO_SECURITY_CORE_CLR_CRITICAL)
249 mono_raise_exception (mono_get_exception_field_access ());
251 /* also it cannot access a fields that is not visible from it's (caller) point of view */
252 if (!check_field_access (caller, field))
253 mono_raise_exception (mono_get_exception_field_access ());
257 * mono_security_core_clr_ensure_reflection_access_method:
259 * Ensure that the specified method can be used with reflection since
260 * Transparent code cannot call Critical methods and can only call them
261 * if they are visible from it's point of view.
263 * A MethodAccessException is thrown if the field is cannot be accessed.
266 mono_security_core_clr_ensure_reflection_access_method (MonoMethod *method)
268 MonoMethod *caller = get_reflection_caller ();
269 /* CoreCLR restrictions applies to Transparent code/caller */
270 if (mono_security_core_clr_method_level (caller, TRUE) != MONO_SECURITY_CORE_CLR_TRANSPARENT)
273 /* Transparent code cannot invoke, even using reflection, Critical code */
274 if (mono_security_core_clr_method_level (method, TRUE) == MONO_SECURITY_CORE_CLR_CRITICAL)
275 mono_raise_exception (mono_get_exception_method_access ());
277 /* also it cannot invoke a method that is not visible from it's (caller) point of view */
278 if (!check_method_access (caller, method))
279 mono_raise_exception (mono_get_exception_method_access ());
283 * can_avoid_corlib_reflection_delegate_optimization:
285 * Mono's mscorlib use delegates to optimize PropertyInfo and EventInfo
286 * reflection calls. This requires either a bunch of additional, and not
287 * really required, [SecuritySafeCritical] in the class libraries or
288 * (like this) a way to skip them. As a bonus we also avoid the stack
289 * walk to find the caller.
291 * Return TRUE if we can skip this "internal" delegate creation, FALSE
295 can_avoid_corlib_reflection_delegate_optimization (MonoMethod *method)
297 if (!mono_security_core_clr_is_platform_image (method->klass->image))
300 if (strcmp (method->klass->name_space, "System.Reflection") != 0)
303 if (strcmp (method->klass->name, "MonoProperty") == 0) {
304 if ((strcmp (method->name, "GetterAdapterFrame") == 0) || strcmp (method->name, "StaticGetterAdapterFrame") == 0)
306 } else if (strcmp (method->klass->name, "EventInfo") == 0) {
307 if ((strcmp (method->name, "AddEventFrame") == 0) || strcmp (method->name, "StaticAddEventAdapterFrame") == 0)
315 * mono_security_core_clr_ensure_delegate_creation:
317 * Return TRUE if a delegate can be created on the specified method.
318 * CoreCLR also affect the binding, so throwOnBindFailure must be
319 * FALSE to let this function return (FALSE) normally, otherwise (if
320 * throwOnBindFailure is TRUE) itwill throw an ArgumentException.
322 * A MethodAccessException is thrown if the specified method is not
323 * visible from the caller point of view.
326 mono_security_core_clr_ensure_delegate_creation (MonoMethod *method, gboolean throwOnBindFailure)
330 /* note: mscorlib creates delegates to avoid reflection (optimization), we ignore those cases */
331 if (can_avoid_corlib_reflection_delegate_optimization (method))
334 caller = get_reflection_caller ();
335 /* if the "real" caller is not Transparent then it do can anything */
336 if (mono_security_core_clr_method_level (caller, TRUE) != MONO_SECURITY_CORE_CLR_TRANSPARENT)
339 /* otherwise it (as a Transparent caller) cannot create a delegate on a Critical method... */
340 if (mono_security_core_clr_method_level (method, TRUE) == MONO_SECURITY_CORE_CLR_CRITICAL) {
341 /* but this throws only if 'throwOnBindFailure' is TRUE */
342 if (!throwOnBindFailure)
345 mono_raise_exception (mono_get_exception_argument ("method", "Transparent code cannot call Critical code"));
348 /* also it cannot create the delegate on a method that is not visible from it's (caller) point of view */
349 if (!check_method_access (caller, method))
350 mono_raise_exception (mono_get_exception_method_access ());
356 * mono_security_core_clr_ensure_dynamic_method_resolved_object:
358 * Called from mono_reflection_create_dynamic_method (reflection.c) to add some extra checks required for CoreCLR.
359 * Dynamic methods needs to check to see if the objects being used (e.g. methods, fields) comes from platform code
360 * and do an accessibility check in this case. Otherwise (i.e. user/application code) can be used without this extra
361 * accessbility check.
364 mono_security_core_clr_ensure_dynamic_method_resolved_object (gpointer ref, MonoClass *handle_class)
366 /* XXX find/create test cases for other handle_class XXX */
367 if (handle_class == mono_defaults.fieldhandle_class) {
368 MonoClassField *field = (MonoClassField*) ref;
369 MonoClass *klass = mono_field_get_parent (field);
370 /* fields coming from platform code have extra protection (accessibility check) */
371 if (mono_security_core_clr_is_platform_image (klass->image)) {
372 MonoMethod *caller = get_reflection_caller ();
373 /* XXX Critical code probably can do this / need some test cases (safer off otherwise) XXX */
374 if (!check_field_access (caller, field))
375 return mono_get_exception_field_access ();
377 } else if (handle_class == mono_defaults.methodhandle_class) {
378 MonoMethod *method = (MonoMethod*) ref;
379 /* methods coming from platform code have extra protection (accessibility check) */
380 if (mono_security_core_clr_is_platform_image (method->klass->image)) {
381 MonoMethod *caller = get_reflection_caller ();
382 /* XXX Critical code probably can do this / need some test cases (safer off otherwise) XXX */
383 if (!check_method_access (caller, method))
384 return mono_get_exception_method_access ();
391 * mono_security_core_clr_level_from_cinfo:
393 * Return the MonoSecurityCoreCLRLevel that match the attribute located
394 * in the specified custom attributes. If no attribute is present it
395 * defaults to MONO_SECURITY_CORE_CLR_TRANSPARENT, which is the default
396 * level for all code under the CoreCLR.
398 static MonoSecurityCoreCLRLevel
399 mono_security_core_clr_level_from_cinfo (MonoCustomAttrInfo *cinfo, MonoImage *image)
401 int level = MONO_SECURITY_CORE_CLR_TRANSPARENT;
403 if (cinfo && mono_custom_attrs_has_attr (cinfo, security_safe_critical_attribute ()))
404 level = MONO_SECURITY_CORE_CLR_SAFE_CRITICAL;
405 if (cinfo && mono_custom_attrs_has_attr (cinfo, security_critical_attribute ()))
406 level = MONO_SECURITY_CORE_CLR_CRITICAL;
412 * mono_security_core_clr_class_level_no_platform_check:
414 * Return the MonoSecurityCoreCLRLevel for the specified class, without
415 * checking for platform code. This help us avoid multiple redundant
417 * - a check for the method and one for the class;
418 * - a check for the class and outer class(es) ...
420 static MonoSecurityCoreCLRLevel
421 mono_security_core_clr_class_level_no_platform_check (MonoClass *class)
423 MonoSecurityCoreCLRLevel level = MONO_SECURITY_CORE_CLR_TRANSPARENT;
424 MonoCustomAttrInfo *cinfo = mono_custom_attrs_from_class (class);
426 level = mono_security_core_clr_level_from_cinfo (cinfo, class->image);
427 mono_custom_attrs_free (cinfo);
430 if (level == MONO_SECURITY_CORE_CLR_TRANSPARENT && class->nested_in)
431 level = mono_security_core_clr_class_level_no_platform_check (class->nested_in);
437 * mono_security_core_clr_class_level:
439 * Return the MonoSecurityCoreCLRLevel for the specified class.
441 MonoSecurityCoreCLRLevel
442 mono_security_core_clr_class_level (MonoClass *class)
444 /* non-platform code is always Transparent - whatever the attributes says */
445 if (!mono_security_core_clr_test && !mono_security_core_clr_is_platform_image (class->image))
446 return MONO_SECURITY_CORE_CLR_TRANSPARENT;
448 return mono_security_core_clr_class_level_no_platform_check (class);
452 * mono_security_core_clr_method_level:
454 * Return the MonoSecurityCoreCLRLevel for the specified method.
455 * If with_class_level is TRUE then the type (class) will also be
456 * checked, otherwise this will only report the information about
459 MonoSecurityCoreCLRLevel
460 mono_security_core_clr_method_level (MonoMethod *method, gboolean with_class_level)
462 MonoCustomAttrInfo *cinfo;
463 MonoSecurityCoreCLRLevel level = MONO_SECURITY_CORE_CLR_TRANSPARENT;
465 /* if get_reflection_caller returns NULL then we assume the caller has NO privilege */
469 /* non-platform code is always Transparent - whatever the attributes says */
470 if (!mono_security_core_clr_test && !mono_security_core_clr_is_platform_image (method->klass->image))
473 cinfo = mono_custom_attrs_from_method (method);
475 level = mono_security_core_clr_level_from_cinfo (cinfo, method->klass->image);
476 mono_custom_attrs_free (cinfo);
479 if (with_class_level && level == MONO_SECURITY_CORE_CLR_TRANSPARENT)
480 level = mono_security_core_clr_class_level (method->klass);
486 * mono_security_core_clr_is_platform_image:
488 * Return the (cached) boolean value indicating if this image represent platform code
491 mono_security_core_clr_is_platform_image (MonoImage *image)
493 return image->core_clr_platform_code;
497 * default_platform_check:
499 * Default platform check. Always return FALSE.
502 default_platform_check (const char *image_name)
507 static MonoCoreClrPlatformCB platform_callback = default_platform_check;
510 * mono_security_core_clr_determine_platform_image:
512 * Call the supplied callback (from mono_security_set_core_clr_platform_callback)
513 * to determine if this image represents platform code.
516 mono_security_core_clr_determine_platform_image (MonoImage *image)
518 return platform_callback (image->name);
522 * mono_security_enable_core_clr:
524 * Enable the verifier and the CoreCLR security model
527 mono_security_enable_core_clr ()
529 mono_verifier_set_mode (MONO_VERIFIER_MODE_VERIFIABLE);
530 mono_security_set_mode (MONO_SECURITY_MODE_CORE_CLR);
534 * mono_security_set_core_clr_platform_callback:
536 * Set the callback function that will be used to determine if an image
537 * is part, or not, of the platform code.
540 mono_security_set_core_clr_platform_callback (MonoCoreClrPlatformCB callback)
542 platform_callback = callback;